Nicolas Nackel / Mbed 2 deprecated PPP-Blinky

Small Internet Protocol Stack using a standard serial port.

Dependencies:   mbed

PPP-Blinky - TCP/IP Networking Over a Serial Port

Note: The source code is at the bottom of this page.

/media/uploads/nixnax/blinky-connected.gif
A Windows desktop showing PPP-Blinky in the network connections list.

Describe PPP-Blinky in Three Sentences

PPP-Blinky is a tiny library that enables Internet protocols (IPv4) to any mbed target hardware by using only a serial port.

The code runs on processors with as little as 8k RAM, for example the Nucleo-L053R8 board.

PPP-Blinky uses the industry-standard PPP (Point-to-Point) Protocol and a tiny "stateless" TCP/IP stack.

No Ethernet Port Required

No ethernet port is required - PPP-Blinky uses a serial port to send IP packets to your PC.

PPP-Blinky emulates a standard dial-up modem and therefore connects to Windows, Linux or Adroid machines.

The code runs on most ARM mbed platforms such as the LPC11U24 shown in the picture below:

/media/uploads/nixnax/blinky-to-laptop1.jpg mbed LPC11u24 acting as a webserver to a Windows laptop.

Webserver

The Webserver and WebSocket functions are ideal for building browser-based GUIs on mbed-enabled hardware.

PPP-Blinky's HTTP webserver works with most web clients such as Internet Explorer, Mozilla Firefox, Google Chrome, Safari, Curl, wget and Lynx as well as Microsoft Powershell Invoke-Webrequest command.

In the image below Firefox web browser displays the main web page embedded into PPP-Blinky's code:

/media/uploads/nixnax/ppp-blinky-firefox.jpg Firefox web browser displays a web page embedded into PPP-Blinky's code

WebSocket Service

WebSocket is the most popular protocol standard for real-time bidirectional TCP/IP communication between clients and servers.
In the image below a small Internet Explorer script has connected to PPP-Blinky's WebSocket Service.
A websocket message was then sent by the browser and was echoed back by the WebSocket, triggering the onmessage event in the script.
The WebSocket service enables bidirectional real-time interaction between PPP-Blinky and any element in the browser DOM via JavaScript.
If you already have PPP-Blinky up and running you can test your WebSocket service using this: http://jsfiddle.net/d26cyuh2/112/embedded/result
Websockets are ideal for building browser-based GUIs for mbed hardware.

/media/uploads/nixnax/ppp-blinky-websocke-2.gif

Trying PPP-Blinky on your mbed board

You will need an mbed-enabled hardware board: https://developer.mbed.org/platforms/

Establish a serial port connection between your host PC and your mbed board. The easiest way is to use mbed hardware with a USB serial debug port. I've tried the ST-Micro Nucleo-L476RG, Nucleo-L152RE, Nucleo-F401RE, Nucleo-L432KC, Nucleo-L053R8, mbed-LPC11U24 and mbed-LPC1768 boards and they all work out of the box. Use the mbed online compiler to compile the software for your target board. Save the compiled binary to your hardware.

Before establishing a network connection, you can verify the operation of the code by opening a terminal program such as Tera Term, and setting the baud rate of the COM port on your mbed board to 115200 baud. LED1 should toggle for every two 0x7E (~) (i.e. tilde) characters you type, as 0x7E is the PPP frame start/end marker. Don't forget to close the port when your'e done testing, or else Windows Dial-up Networking will report that the COM port is in use by another program when you try to connect.

Once you are certain that the serial port and firmware is working, proceed to creating a new network connection on your PC -see below.

Creating a Dial-up Connection in Windows

/media/uploads/nixnax/modem.jpg

Setting up Dial-Up Networking (DUN) on your Windows 7 or 8 PC is essentially a two-step process: First, you create a new modem device, because PPP-blinky partially emulates a standard Windows serial port modem device. Second, you create a new Internet connection (in practice, a new network adapter) which is associated with your new "modem".

Step-by-step description of how to configure Windows for PPP-Blinky here:

/users/nixnax/code/PPP-Blinky/wiki/Configuring-Windows-Dial-Up-Networking

There is also a screen on how to set up Linux dial-up networking near the bottom of this page.

Connecting to PPP-Blinky from your PC

Once Windows networking is configured you can establish a dial-up connection to your mbed board over the USB virtual com port.

The IP address you manually assigned to the new dial-up network adapter (172.10.10.1) functions as a gateway to any valid IP address on that subnet. In the screen capture below, I'm sending pings from the Windows 8 command line to my ST-Micro Nucleo-L476RG board over the USB virtual serial Port. I'm also using a second serial port and Tera Term to capture the debug output from a second serial port on the hardware. The optional debug output from the board prints out the IP source and destination address and the first few bytes of the data payload. Note that the source is the adapter IP address, (172.10.10.1 in this case) and the destination is some other address on that subnet - all packets to the subnet are sent to our mbed hardware. For example, you could also ping 172.10.10.123 or, if your PPP-Blinky is running, simply click on this link: http://172.10.10.123

/media/uploads/nixnax/ping-cap-3.gif

One Million Pings!

In the image below the ICMP ("ping") echo reply service was tested by sending one million pings to ppp-Blinky. This took over two hours.
The ping tool used on the Windows 8 PC was psping.exe from PsTools by Mark Russinovich - http://bit.ly/PingFast
The average reply time for a short ping (1 byte of payload data) was 11 milliseconds at 115200 baud on the $10 Nucleo-L053R8 board - barely enough time for 130 bytes to be sent over the port!

/media/uploads/nixnax/ppp-blinky-ping-results.jpg

Monitoring PPP-Blinky Packets

The image below is from a Microsoft Network Monitor 3.4 capture session.

Responses from PPP-Blinky are shown in blue.

Frame 2 - Internet Explorer at IP 172.10.10.1 (the Dial-Up Adapter IP) requests a TCP connection by sending an S (SYN) flag.
Frame 3 - PPP-Blinky at IP 172.10.10.2 responds with an ACK in frame 3. One direction of the link is now established.
Frame 4 - The PC acknowledges the SYN sent by PPP-Blinky in frame 3. The TCP link is now fully established.
Frame 5 - The browser "pushes" (P flag is set) an HTTP GET request to PPP-Blinky.
Frame 6 - PPP-Blinky responds with a standard HTTP response "pushes" (P flag set) back a small web page. It also sets the A (ACK) flag to acknowledge the message sent in frame 6.
Frame 7 - The PC acknowledges reception of the HTTP payload.
Frame 8 - The PC starts to shut down the TCP connection by sending a FIN flag.
Frame 9 - PPP-Blinky acknowledges the FIN request - the connection is now closed in one direction. It also sets a FIN flag in the response to request closure of the opposite direction of the connection.
Frame 10 - The PC acknowledges the FIN request. The closing of the TCP connection is now confirmed in both directions.

/media/uploads/nixnax/ms-network-monitor-http-get-1.gif

Debug Output

PPP-Blinky can output handy debug information to an optional second serial port.
The image below shows the debug output (Ident, Source, Destination, TCP Flags) for a complete HTTP conversation.
The PC messages are displayed in black. PPP-Blinky messages are blue.
Notice how PPP-blinky automatically inserts a blank line after each full HTTP conversation.

/media/uploads/nixnax/tcp-data-3.gif

Creating a Dial-Up Connection in Linux

The screen below shows the required pppd command to connect to PPP-Blinky from a Linux machine. This was much simpler than Windows! The USB serial port of the mbed LPC1768 board registered as /dev/ttyACM0 on my Linux box. Do a websearch on pppd if you want to learn more about pppd, the Linux PPP handler. Near the bottom of the screen below, two webpages are fetched (/ and /y) by using the curl command on the command line. Gnome Webkit and Firefox work fine, too. Also try echo GET / HTTP/1.1 | nc 172.10.10.2 which uses netcat, the "Swiss army knife" of networking tools. PPP-Blinky was also tested with ApacheBench, the Apache server benchmark software. After 100000 fetches, the mean page fetch rate was reported as 6 page fetches per second for a small page.

/media/uploads/nixnax/pppd-screen.png

Caveats

PPP Blinky is an extremely sparse implementation (1.5k lines) of HTTP,WebSocket,TCP, UDP, ICMP, IPCP and LCP over PPP, requiring around 8kB of RAM. The minimum functionality required to establish connectivity is implemented. These are often acceptable tradeoffs for embedded projects as well as a handy tool to learn the practical details of everyday networking implementations.

main.cpp@31:e000c1b9c565, 2017-01-05 (annotated)

Committer:
nixnax
Date:
Thu Jan 05 02:16:53 2017 +0000
Revision:
31:e000c1b9c565
Parent:
30:273431bccb02
Child:
32:512228c29209
Made seq and ack UNSIGNED ints

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nixnax 0:2cf4880c312a 1 #include "mbed.h"
nixnax 0:2cf4880c312a 2
nixnax 29:30de79d658f6 3 // Copyright 2016 Nicolas Nackel aka Nixnax. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
nixnax 12:db0dc91f0231 4
nixnax 0:2cf4880c312a 5 // Proof-of-concept for TCP/IP using Windows 7/8/10 Dial Up Networking over MBED USB Virtual COM Port
nixnax 0:2cf4880c312a 6
nixnax 4:a469050d5b80 7 // Toggles LED1 every time the PC sends an IP packet over the PPP link
nixnax 4:a469050d5b80 8
nixnax 29:30de79d658f6 9 // Note - turn off all Dial Up authentication, passwords, compression options - Simplest link possible.
nixnax 29:30de79d658f6 10 // Be sure to read the section on mbed on "Windows 7/8/10 PPP bug" if you keep on getting Dial Up Error 777.
nixnax 0:2cf4880c312a 11
nixnax 9:0992486d4a30 12 // Handy links
nixnax 29:30de79d658f6 13 // https://developer.mbed.org/users/nixnax/code/PPP-Blinky/ - Handy Notes, Instructions and introduction
nixnax 6:fba4c2e817b8 14 // http://atari.kensclassics.org/wcomlog.htm
nixnax 6:fba4c2e817b8 15 // https://technet.microsoft.com/en-us/library/cc957992.aspx
nixnax 9:0992486d4a30 16 // https://en.wikibooks.org/wiki/Serial_Programming/IP_Over_Serial_Connections
nixnax 6:fba4c2e817b8 17
nixnax 29:30de79d658f6 18 // Handy tools
nixnax 29:30de79d658f6 19 // https://ttssh2.osdn.jp/index.html.en - A good terminal program to monitor the debug output from the second serial port with!
nixnax 29:30de79d658f6 20 // Wireshark - can't monitor Dial-Up network packets on windows, but very hand - can import our dumpFrame routine's hex output
nixnax 29:30de79d658f6 21 // Microsoft network monitor - real-time monitoring of all our packets
nixnax 29:30de79d658f6 22 // http://pingtester.net/ - nice tool for high rate ping testing
nixnax 29:30de79d658f6 23 // http://www.sunshine2k.de/coding/javascript/crc/crc_js.html - Correctly calculates the 16-bit FCS (crc) on our frames (Choose CRC16_CCITT_FALSE)
nixnax 29:30de79d658f6 24 // The curl program in Windows Powershell - use like this to test the webserver: while (1) { curl 172.10.10.1 }
nixnax 29:30de79d658f6 25 // https://technet.microsoft.com/en-us/sysinternals/pstools.aspx - psping for fast testing of ICMP ping function
nixnax 29:30de79d658f6 26 // https://eternallybored.org/misc/netcat/ - use netcat -u 172.10.10.1 80 to send/receive UDP packets from our board
nixnax 0:2cf4880c312a 27
nixnax 29:30de79d658f6 28 Serial pc(USBTX, USBRX); // The USB com port - Set this up as a Dial-Up Modem on your pc
nixnax 29:30de79d658f6 29 Serial xx(PC_10, PC_11); // See debug messages here. Not necessary to work, but VERY interesting output!
nixnax 29:30de79d658f6 30
nixnax 29:30de79d658f6 31 int v0=1;
nixnax 29:30de79d658f6 32 int v1=1; // verbosity flags used in debug printouts - change to 1/0 to see more/less debug info
nixnax 29:30de79d658f6 33
nixnax 29:30de79d658f6 34 // the commented #define below gets rid of ALL the debug printfs
nixnax 20:5db9b77b38a6 35 #define debug(x) xx.printf x
nixnax 19:e53cdee9a33c 36 //#define debug(x) {}
nixnax 9:0992486d4a30 37
nixnax 29:30de79d658f6 38 DigitalOut led1(LED1); // this led toggles when a packet is received
nixnax 4:a469050d5b80 39
nixnax 29:30de79d658f6 40 // the standard hdlc frame start/end character
nixnax 4:a469050d5b80 41 #define FRAME_7E (0x7e)
nixnax 29:30de79d658f6 42
nixnax 29:30de79d658f6 43 // the serial port receive buffer and packet buffer
nixnax 29:30de79d658f6 44 #define BUFLEN (1<<12)
nixnax 20:5db9b77b38a6 45 char rxbuf[BUFLEN];
nixnax 29:30de79d658f6 46 char frbuf[3000]; // send/receive buffer for ppp frames
nixnax 0:2cf4880c312a 47
nixnax 29:30de79d658f6 48 // a structure to keep all our ppp globals in
nixnax 29:30de79d658f6 49 struct pppType {
nixnax 29:30de79d658f6 50 int online;
nixnax 26:11f4eb2663a7 51 int ident;
nixnax 28:1aa629be05e7 52 int sync;
nixnax 31:e000c1b9c565 53 unsigned int seq;
nixnax 29:30de79d658f6 54 int crc;
nixnax 29:30de79d658f6 55 int ledState;
nixnax 4:a469050d5b80 56 struct {
nixnax 20:5db9b77b38a6 57 char * buf;
nixnax 29:30de79d658f6 58 volatile int head;
nixnax 29:30de79d658f6 59 volatile int tail;
nixnax 9:0992486d4a30 60 int total;
nixnax 4:a469050d5b80 61 } rx; // serial port buffer
nixnax 4:a469050d5b80 62 struct {
nixnax 6:fba4c2e817b8 63 int id;
nixnax 4:a469050d5b80 64 int len;
nixnax 4:a469050d5b80 65 int crc;
nixnax 4:a469050d5b80 66 char * buf;
nixnax 4:a469050d5b80 67 } pkt; // ppp buffer
nixnax 29:30de79d658f6 68 };
nixnax 31:e000c1b9c565 69
nixnax 29:30de79d658f6 70 pppType ppp; // our global - definitely not thread safe
nixnax 0:2cf4880c312a 71
nixnax 29:30de79d658f6 72 // intitialize our globals
nixnax 29:30de79d658f6 73 void pppInitStruct()
nixnax 29:30de79d658f6 74 {
nixnax 29:30de79d658f6 75 ppp.online=0;
nixnax 29:30de79d658f6 76 ppp.rx.buf=rxbuf;
nixnax 29:30de79d658f6 77 ppp.rx.tail=0;
nixnax 29:30de79d658f6 78 ppp.rx.head=0;
nixnax 29:30de79d658f6 79 ppp.rx.total=0;
nixnax 29:30de79d658f6 80 ppp.pkt.buf=frbuf;
nixnax 29:30de79d658f6 81 ppp.pkt.len=0;
nixnax 29:30de79d658f6 82 ppp.ident=0;
nixnax 29:30de79d658f6 83 ppp.sync=0;
nixnax 29:30de79d658f6 84 ppp.seq=77;
nixnax 29:30de79d658f6 85 ppp.ledState=0;
nixnax 29:30de79d658f6 86 }
nixnax 26:11f4eb2663a7 87
nixnax 29:30de79d658f6 88 void crcReset()
nixnax 29:30de79d658f6 89 {
nixnax 29:30de79d658f6 90 ppp.crc=0xffff; // crc restart
nixnax 29:30de79d658f6 91 }
nixnax 4:a469050d5b80 92
nixnax 29:30de79d658f6 93 void crcDo(int x) // cumulative crc
nixnax 29:30de79d658f6 94 {
nixnax 29:30de79d658f6 95 for (int i=0; i<8; i++) {
nixnax 29:30de79d658f6 96 ppp.crc=((ppp.crc&1)^(x&1))?(ppp.crc>>1)^0x8408:ppp.crc>>1; // crc calculator
nixnax 29:30de79d658f6 97 x>>=1;
nixnax 29:30de79d658f6 98 }
nixnax 29:30de79d658f6 99 }
nixnax 29:30de79d658f6 100
nixnax 29:30de79d658f6 101 int crcBuf(char * buf, int size) // crc on an entire block of memory
nixnax 29:30de79d658f6 102 {
nixnax 31:e000c1b9c565 103 crcReset();
nixnax 31:e000c1b9c565 104 for(int i=0; i<size; i++)crcDo(*buf++);
nixnax 29:30de79d658f6 105 return ppp.crc;
nixnax 29:30de79d658f6 106 }
nixnax 0:2cf4880c312a 107
nixnax 0:2cf4880c312a 108 void rxHandler() // serial port receive interrupt handler
nixnax 0:2cf4880c312a 109 {
nixnax 17:4918c893d802 110 while ( pc.readable() ) {
nixnax 20:5db9b77b38a6 111 int hd = (ppp.rx.head+1)&(BUFLEN-1); // increment/wrap
nixnax 20:5db9b77b38a6 112 if ( hd == ppp.rx.tail ) break; // watch for buffer full
nixnax 17:4918c893d802 113 ppp.rx.buf[ppp.rx.head]=pc.getc(); // insert in rx buffer
nixnax 20:5db9b77b38a6 114 ppp.rx.head = hd; // update head pointer
nixnax 15:b0154c910143 115 }
nixnax 0:2cf4880c312a 116 }
nixnax 0:2cf4880c312a 117
nixnax 29:30de79d658f6 118 void led1Toggle()
nixnax 29:30de79d658f6 119 {
nixnax 29:30de79d658f6 120 ppp.ledState = ppp.ledState? 0 : 1;
nixnax 29:30de79d658f6 121 led1 = ppp.ledState;
nixnax 14:c65831c25aaa 122 }
nixnax 14:c65831c25aaa 123
nixnax 22:00df34cd4d7e 124 int rxbufNotEmpty() // check if rx buffer has data
nixnax 0:2cf4880c312a 125 {
nixnax 22:00df34cd4d7e 126 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 127 int notEmpty = (ppp.rx.head==ppp.rx.tail) ? 0 : 1 ;
nixnax 22:00df34cd4d7e 128 __enable_irq(); // critical section end
nixnax 22:00df34cd4d7e 129 return notEmpty;
nixnax 0:2cf4880c312a 130 }
nixnax 0:2cf4880c312a 131
nixnax 0:2cf4880c312a 132 int pc_getBuf() // get one character from the buffer
nixnax 0:2cf4880c312a 133 {
nixnax 22:00df34cd4d7e 134 if ( rxbufNotEmpty() ) {
nixnax 4:a469050d5b80 135 int x = ppp.rx.buf[ ppp.rx.tail ];
nixnax 20:5db9b77b38a6 136 __disable_irq(); // critical section start
nixnax 29:30de79d658f6 137 ppp.rx.tail=(ppp.rx.tail+1)&(BUFLEN-1);
nixnax 20:5db9b77b38a6 138 __enable_irq(); // critical section end
nixnax 0:2cf4880c312a 139 return x;
nixnax 20:5db9b77b38a6 140 } else return -1;
nixnax 0:2cf4880c312a 141 }
nixnax 0:2cf4880c312a 142
nixnax 4:a469050d5b80 143 void scanForConnectString(); // scan for connect attempts from pc
nixnax 1:9e03798d4367 144
nixnax 29:30de79d658f6 145 void processFrame(int start, int end) // process received frame
nixnax 29:30de79d658f6 146 {
nixnax 14:c65831c25aaa 147 led1Toggle(); // change led1 state when frames are received
nixnax 29:30de79d658f6 148 if(start==end) {
nixnax 29:30de79d658f6 149 pc.putc(0x7e);
nixnax 29:30de79d658f6 150 return;
nixnax 29:30de79d658f6 151 }
nixnax 9:0992486d4a30 152 crcReset();
nixnax 9:0992486d4a30 153 char * dest = ppp.pkt.buf;
nixnax 9:0992486d4a30 154 ppp.pkt.len=0;
nixnax 9:0992486d4a30 155 int unstuff=0;
nixnax 17:4918c893d802 156 int idx = start;
nixnax 17:4918c893d802 157 while(1) {
nixnax 9:0992486d4a30 158 if (unstuff==0) {
nixnax 29:30de79d658f6 159 if (rxbuf[idx]==0x7d) unstuff=1;
nixnax 29:30de79d658f6 160 else {
nixnax 29:30de79d658f6 161 *dest = rxbuf[idx];
nixnax 29:30de79d658f6 162 ppp.pkt.len++;
nixnax 29:30de79d658f6 163 dest++;
nixnax 29:30de79d658f6 164 crcDo(rxbuf[idx]);
nixnax 29:30de79d658f6 165 }
nixnax 12:db0dc91f0231 166 } else { // unstuff
nixnax 29:30de79d658f6 167 *dest = rxbuf[idx]^0x20;
nixnax 29:30de79d658f6 168 ppp.pkt.len++;
nixnax 29:30de79d658f6 169 dest++;
nixnax 29:30de79d658f6 170 crcDo(rxbuf[idx]^0x20);
nixnax 9:0992486d4a30 171 unstuff=0;
nixnax 9:0992486d4a30 172 }
nixnax 17:4918c893d802 173 idx = (idx+1) & (BUFLEN-1);
nixnax 17:4918c893d802 174 if (idx == end) break;
nixnax 9:0992486d4a30 175 }
nixnax 29:30de79d658f6 176 ppp.pkt.crc = ppp.crc & 0xffff;
nixnax 9:0992486d4a30 177 if (ppp.pkt.crc == 0xf0b8) { // check for good CRC
nixnax 16:cb0b80c24ba2 178 void determinePacketType(); // declaration only
nixnax 9:0992486d4a30 179 determinePacketType();
nixnax 29:30de79d658f6 180 } else if (v0) {
nixnax 29:30de79d658f6 181 debug(("PPP FCS(crc) Error CRC=%x Length = %d\n",ppp.pkt.crc,ppp.pkt.len));
nixnax 9:0992486d4a30 182 }
nixnax 9:0992486d4a30 183 }
nixnax 9:0992486d4a30 184
nixnax 29:30de79d658f6 185 // Note - the hex output of dumpframe can be imported into WireShark
nixnax 29:30de79d658f6 186 // Copy the frame's hex output from your terminal program and save as a text file
nixnax 29:30de79d658f6 187 // In WireShark, use "Import Hex File". Options are No Offset, protocol=PPP.
nixnax 29:30de79d658f6 188 void dumpFrame()
nixnax 29:30de79d658f6 189 {
nixnax 29:30de79d658f6 190 for(int i=0; i<ppp.pkt.len; i++) debug(("%02x ", ppp.pkt.buf[i]));
nixnax 16:cb0b80c24ba2 191 debug((" C=%02x %02x L=%d\n", ppp.pkt.crc&0xff, (ppp.pkt.crc>>8)&0xff, ppp.pkt.len));
nixnax 16:cb0b80c24ba2 192 }
nixnax 16:cb0b80c24ba2 193
nixnax 29:30de79d658f6 194 void hdlcPut(int ch) // do hdlc handling of special (flag) characters
nixnax 29:30de79d658f6 195 {
nixnax 29:30de79d658f6 196 if ( (ch<0x20) || (ch==0x7d) || (ch==0x7e) ) {
nixnax 29:30de79d658f6 197 pc.putc(0x7d);
nixnax 29:30de79d658f6 198 pc.putc(ch^0x20);
nixnax 29:30de79d658f6 199 } else {
nixnax 29:30de79d658f6 200 pc.putc(ch);
nixnax 29:30de79d658f6 201 }
nixnax 11:f58998c24f0b 202 }
nixnax 9:0992486d4a30 203
nixnax 29:30de79d658f6 204 void sendFrame()
nixnax 29:30de79d658f6 205 {
nixnax 17:4918c893d802 206 int crc = crcBuf(ppp.pkt.buf, ppp.pkt.len-2); // update crc
nixnax 12:db0dc91f0231 207 ppp.pkt.buf[ ppp.pkt.len-2 ] = (~crc>>0); // fcs lo (crc)
nixnax 12:db0dc91f0231 208 ppp.pkt.buf[ ppp.pkt.len-1 ] = (~crc>>8); // fcs hi (crc)
nixnax 16:cb0b80c24ba2 209 pc.putc(0x7e); // hdlc start-of-frame "flag"
nixnax 29:30de79d658f6 210 for(int i=0; i<ppp.pkt.len; i++) hdlcPut( ppp.pkt.buf[i] );
nixnax 16:cb0b80c24ba2 211 pc.putc(0x7e); // hdlc end-of-frame "flag"
nixnax 9:0992486d4a30 212 }
nixnax 9:0992486d4a30 213
nixnax 29:30de79d658f6 214 void ipRequestHandler()
nixnax 29:30de79d658f6 215 {
nixnax 15:b0154c910143 216 debug(("IPCP Conf "));
nixnax 9:0992486d4a30 217 if ( ppp.pkt.buf[7] != 4 ) {
nixnax 15:b0154c910143 218 debug(("Rej\n")); // reject if any options are requested
nixnax 9:0992486d4a30 219 ppp.pkt.buf[4]=4;
nixnax 9:0992486d4a30 220 sendFrame();
nixnax 9:0992486d4a30 221 } else {
nixnax 15:b0154c910143 222 debug(("Ack\n"));
nixnax 9:0992486d4a30 223 ppp.pkt.buf[4]=2; // ack the minimum
nixnax 9:0992486d4a30 224 sendFrame(); // acknowledge
nixnax 29:30de79d658f6 225 debug(("IPCP Ask\n"));
nixnax 9:0992486d4a30 226 // send our own request now
nixnax 12:db0dc91f0231 227 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 228 ppp.pkt.buf[5]++; // next sequence
nixnax 9:0992486d4a30 229 sendFrame(); // this is our request
nixnax 9:0992486d4a30 230 }
nixnax 9:0992486d4a30 231 }
nixnax 9:0992486d4a30 232
nixnax 29:30de79d658f6 233 void ipAckHandler()
nixnax 29:30de79d658f6 234 {
nixnax 29:30de79d658f6 235 debug(("IPCP Grant\n"));
nixnax 29:30de79d658f6 236 }
nixnax 9:0992486d4a30 237
nixnax 29:30de79d658f6 238 void ipNackHandler()
nixnax 29:30de79d658f6 239 {
nixnax 29:30de79d658f6 240 debug(("IPCP Nack\n"));
nixnax 29:30de79d658f6 241 }
nixnax 9:0992486d4a30 242
nixnax 29:30de79d658f6 243 void ipDefaultHandler()
nixnax 29:30de79d658f6 244 {
nixnax 29:30de79d658f6 245 debug(("IPCP Other\n"));
nixnax 29:30de79d658f6 246 }
nixnax 29:30de79d658f6 247
nixnax 29:30de79d658f6 248 void IPCPframe()
nixnax 29:30de79d658f6 249 {
nixnax 9:0992486d4a30 250 int code = ppp.pkt.buf[4]; // packet type is here
nixnax 9:0992486d4a30 251 switch (code) {
nixnax 29:30de79d658f6 252 case 1:
nixnax 29:30de79d658f6 253 ipRequestHandler();
nixnax 29:30de79d658f6 254 break;
nixnax 29:30de79d658f6 255 case 2:
nixnax 29:30de79d658f6 256 ipAckHandler();
nixnax 29:30de79d658f6 257 break;
nixnax 29:30de79d658f6 258 case 3:
nixnax 29:30de79d658f6 259 ipNackHandler();
nixnax 29:30de79d658f6 260 break;
nixnax 29:30de79d658f6 261 default:
nixnax 29:30de79d658f6 262 ipDefaultHandler();
nixnax 9:0992486d4a30 263 }
nixnax 29:30de79d658f6 264 }
nixnax 9:0992486d4a30 265
nixnax 29:30de79d658f6 266 void UDPpacket()
nixnax 29:30de79d658f6 267 {
nixnax 12:db0dc91f0231 268 char * udpPkt = ppp.pkt.buf+4; // udp packet start
nixnax 16:cb0b80c24ba2 269 int headerSizeIP = (( udpPkt[0]&0xf)*4);
nixnax 29:30de79d658f6 270 char * udpBlock = udpPkt + headerSizeIP; // udp info start
nixnax 12:db0dc91f0231 271 char * udpSrc = udpBlock; // source port
nixnax 12:db0dc91f0231 272 char * udpDst = udpBlock+2; // destination port
nixnax 12:db0dc91f0231 273 char * udpLen = udpBlock+4; // udp data length
nixnax 12:db0dc91f0231 274 char * udpInf = udpBlock+8; // actual start of info
nixnax 12:db0dc91f0231 275 int srcPort = (udpSrc[0]<<8) | udpSrc[1];
nixnax 12:db0dc91f0231 276 int dstPort = (udpDst[0]<<8) | udpDst[1];
nixnax 12:db0dc91f0231 277 char * srcIP = udpPkt+12; // udp src addr
nixnax 12:db0dc91f0231 278 char * dstIP = udpPkt+16; // udp dst addr
nixnax 29:30de79d658f6 279 #define UDP_HEADER_SIZE 8
nixnax 12:db0dc91f0231 280 int udpLength = ((udpLen[0]<<8) | udpLen[1]) - UDP_HEADER_SIZE; // size of the actual udp data
nixnax 29:30de79d658f6 281 if(v1) debug(("UDP %d.%d.%d.%d:%d ", srcIP[0],srcIP[1],srcIP[2],srcIP[3],srcPort));
nixnax 29:30de79d658f6 282 if(v1) debug(("%d.%d.%d.%d:%d ", dstIP[1],dstIP[1],dstIP[1],dstIP[1],dstPort));
nixnax 15:b0154c910143 283 debug(("Len %d ", udpLength));
nixnax 29:30de79d658f6 284 int printSize = udpLength;
nixnax 29:30de79d658f6 285 if (printSize > 20) printSize = 20; // print only first 20 characters
nixnax 29:30de79d658f6 286 if (v0) {
nixnax 29:30de79d658f6 287 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 288 char ch = udpInf[i];
nixnax 29:30de79d658f6 289 if (ch>31 && ch<127) {
nixnax 29:30de79d658f6 290 debug(("%c", ch));
nixnax 29:30de79d658f6 291 } else {
nixnax 29:30de79d658f6 292 debug(("_"));
nixnax 29:30de79d658f6 293 }
nixnax 29:30de79d658f6 294 }
nixnax 29:30de79d658f6 295 debug(("\n"));
nixnax 29:30de79d658f6 296 }
nixnax 12:db0dc91f0231 297 }
nixnax 11:f58998c24f0b 298
nixnax 29:30de79d658f6 299 int dataCheckSum(char * ptr, int len)
nixnax 29:30de79d658f6 300 {
nixnax 29:30de79d658f6 301 int sum=0;
nixnax 29:30de79d658f6 302 int placeHolder;
nixnax 29:30de79d658f6 303 if (len&1) {
nixnax 29:30de79d658f6 304 placeHolder = ptr[len-1]; // when length is odd zero stuff
nixnax 29:30de79d658f6 305 ptr[len-1]=0;
nixnax 29:30de79d658f6 306 }
nixnax 29:30de79d658f6 307 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 308 int hi = *ptr;
nixnax 29:30de79d658f6 309 ptr++;
nixnax 29:30de79d658f6 310 int lo = *ptr;
nixnax 29:30de79d658f6 311 ptr++;
nixnax 11:f58998c24f0b 312 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 313 sum = sum + val;
nixnax 11:f58998c24f0b 314 }
nixnax 11:f58998c24f0b 315 sum = sum + (sum>>16);
nixnax 29:30de79d658f6 316 if (len&1) {
nixnax 29:30de79d658f6 317 ptr[len-1] = placeHolder; // restore the last byte for odd lengths
nixnax 29:30de79d658f6 318 }
nixnax 12:db0dc91f0231 319 return ~sum;
nixnax 29:30de79d658f6 320 }
nixnax 11:f58998c24f0b 321
nixnax 29:30de79d658f6 322 void headerCheckSum()
nixnax 29:30de79d658f6 323 {
nixnax 11:f58998c24f0b 324 int len =(ppp.pkt.buf[4]&0xf)*4; // length of header in bytes
nixnax 11:f58998c24f0b 325 char * ptr = ppp.pkt.buf+4; // start of ip packet
nixnax 11:f58998c24f0b 326 int sum=0;
nixnax 11:f58998c24f0b 327
nixnax 29:30de79d658f6 328 for (int i=0; i<len/2; i++) {
nixnax 29:30de79d658f6 329 int hi = *ptr;
nixnax 29:30de79d658f6 330 ptr++;
nixnax 29:30de79d658f6 331 int lo = *ptr;
nixnax 29:30de79d658f6 332 ptr++;
nixnax 11:f58998c24f0b 333 int val = ( lo & 0xff ) | ( (hi<<8) & 0xff00 );
nixnax 11:f58998c24f0b 334 sum = sum + val;
nixnax 11:f58998c24f0b 335 }
nixnax 11:f58998c24f0b 336 sum = sum + (sum>>16);
nixnax 11:f58998c24f0b 337 sum = ~sum;
nixnax 11:f58998c24f0b 338 ppp.pkt.buf[14]= (sum>>8);
nixnax 11:f58998c24f0b 339 ppp.pkt.buf[15]= (sum );
nixnax 29:30de79d658f6 340 }
nixnax 9:0992486d4a30 341
nixnax 29:30de79d658f6 342 void ICMPpacket() // internet control message protocol
nixnax 29:30de79d658f6 343 {
nixnax 12:db0dc91f0231 344 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 12:db0dc91f0231 345 char * pktLen = ipPkt+2;
nixnax 12:db0dc91f0231 346 int packetLength = (pktLen[0]<<8) | pktLen[1]; // icmp packet length
nixnax 16:cb0b80c24ba2 347 int headerSizeIP = (( ipPkt[0]&0xf)*4);
nixnax 16:cb0b80c24ba2 348 char * icmpType = ipPkt + headerSizeIP; // icmp data start
nixnax 13:d882b8a042b4 349 char * icmpSum = icmpType+2; // icmp checksum
nixnax 29:30de79d658f6 350 #define ICMP_TYPE_PING_REQUEST 8
nixnax 29:30de79d658f6 351 if ( icmpType[0] == ICMP_TYPE_PING_REQUEST ) {
nixnax 12:db0dc91f0231 352 char * ipTTL = ipPkt+8; // time to live
nixnax 12:db0dc91f0231 353 ipTTL[0]--; // decrement time to live
nixnax 12:db0dc91f0231 354 char * srcAdr = ipPkt+12;
nixnax 12:db0dc91f0231 355 char * dstAdr = ipPkt+16;
nixnax 18:3e35de1bc877 356 int icmpIdent = (icmpType[4]<<8)|icmpType[5];
nixnax 29:30de79d658f6 357 int icmpSequence = (icmpType[6]<<8)|icmpType[7];
nixnax 25:0b0450e1b08b 358 debug(("ICMP PING %d.%d.%d.d %d.%d.%d.%d ", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3],dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]));
nixnax 25:0b0450e1b08b 359 debug(("Ident %04x Sequence %04d ",icmpIdent,icmpSequence));
nixnax 29:30de79d658f6 360 char src[4];
nixnax 29:30de79d658f6 361 char dst[4];
nixnax 12:db0dc91f0231 362 memcpy(src, srcAdr,4);
nixnax 12:db0dc91f0231 363 memcpy(dst, dstAdr,4);
nixnax 12:db0dc91f0231 364 memcpy(srcAdr, dst,4);
nixnax 12:db0dc91f0231 365 memcpy(dstAdr, src,4); // swap src & dest ip
nixnax 12:db0dc91f0231 366 char * chkSum = ipPkt+10;
nixnax 29:30de79d658f6 367 chkSum[0]=0;
nixnax 29:30de79d658f6 368 chkSum[1]=0;
nixnax 12:db0dc91f0231 369 headerCheckSum(); // new ip header checksum
nixnax 29:30de79d658f6 370 #define ICMP_TYPE_ECHO_REPLY 0
nixnax 16:cb0b80c24ba2 371 icmpType[0]=ICMP_TYPE_ECHO_REPLY; // icmp echo reply
nixnax 29:30de79d658f6 372 icmpSum[0]=0;
nixnax 29:30de79d658f6 373 icmpSum[1]=0; // zero the checksum for recalculation
nixnax 16:cb0b80c24ba2 374 int icmpLength = packetLength - headerSizeIP; // length of ICMP data portion
nixnax 16:cb0b80c24ba2 375 int sum = dataCheckSum( icmpType, icmpLength); // this checksum on icmp data portion
nixnax 29:30de79d658f6 376 icmpSum[0]=sum>>8;
nixnax 29:30de79d658f6 377 icmpSum[1]=sum; // new checksum for ICMP data portion
nixnax 16:cb0b80c24ba2 378
nixnax 16:cb0b80c24ba2 379 int printSize = icmpLength-8; // exclude size of icmp header
nixnax 25:0b0450e1b08b 380 char * icmpData = icmpType+8; // the actual payload data is after the header
nixnax 25:0b0450e1b08b 381 if (printSize > 10) printSize = 10; // print up to 20 characters
nixnax 29:30de79d658f6 382 if (v0) {
nixnax 29:30de79d658f6 383 for (int i=0; i<printSize; i++) {
nixnax 29:30de79d658f6 384 char ch = icmpData[i];
nixnax 29:30de79d658f6 385 if (ch>31 && ch<127) {
nixnax 29:30de79d658f6 386 debug(("%c",ch));
nixnax 29:30de79d658f6 387 } else {
nixnax 29:30de79d658f6 388 debug(("_"));
nixnax 29:30de79d658f6 389 }
nixnax 29:30de79d658f6 390 }
nixnax 29:30de79d658f6 391 debug(("\n"));
nixnax 29:30de79d658f6 392 }
nixnax 15:b0154c910143 393 sendFrame(); // reply to the ping
nixnax 29:30de79d658f6 394
nixnax 12:db0dc91f0231 395 } else {
nixnax 29:30de79d658f6 396 if (v0) {
nixnax 29:30de79d658f6 397 debug(("ICMP type=%d \n", icmpType[0]));
nixnax 29:30de79d658f6 398 }
nixnax 11:f58998c24f0b 399 }
nixnax 11:f58998c24f0b 400 }
nixnax 11:f58998c24f0b 401
nixnax 29:30de79d658f6 402 void IGMPpacket() // internet group management protocol
nixnax 29:30de79d658f6 403 {
nixnax 29:30de79d658f6 404 if (v0) {
nixnax 29:30de79d658f6 405 debug(("IGMP type=%d \n", ppp.pkt.buf[28]));
nixnax 29:30de79d658f6 406 }
nixnax 29:30de79d658f6 407 }
nixnax 11:f58998c24f0b 408
nixnax 29:30de79d658f6 409 void dumpHeaderIP ()
nixnax 29:30de79d658f6 410 {
nixnax 26:11f4eb2663a7 411 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 412 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 413 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 414 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 415 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 416 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 417 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 418 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 419 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 420 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 421 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 422 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 423 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 424
nixnax 29:30de79d658f6 425 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 426 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 427 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 428 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 429 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 430 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 431 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 432 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 433 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 434 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 435 char srcIP [16];
nixnax 29:30de79d658f6 436 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 437 char dstIP [16];
nixnax 29:30de79d658f6 438 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 26:11f4eb2663a7 439 debug(("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength));
nixnax 29:30de79d658f6 440 if (v1) debug(("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP));
nixnax 29:30de79d658f6 441 }
nixnax 26:11f4eb2663a7 442
nixnax 29:30de79d658f6 443 void dumpHeaderTCP()
nixnax 29:30de79d658f6 444 {
nixnax 29:30de79d658f6 445 int headerSizeIP = (ppp.pkt.buf[4]&0xf)*4; // header size of ip portion
nixnax 29:30de79d658f6 446 char * tcpStart = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 29:30de79d658f6 447 char * seqtcp = tcpStart + 4; // 4 bytes
nixnax 29:30de79d658f6 448 char * acktcp = tcpStart + 8; // 4 bytes
nixnax 29:30de79d658f6 449 char * flagbitstcp = tcpStart + 12; // 9 bits
nixnax 31:e000c1b9c565 450 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 451 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 26:11f4eb2663a7 452 int flags = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 10:74f8233f72c0 453
nixnax 29:30de79d658f6 454 char flagInfo[10];
nixnax 29:30de79d658f6 455 memset(flagInfo,'.',10); // text presentation of TCP flags
nixnax 29:30de79d658f6 456 if (flags & (1<<0)) flagInfo[0]='F';
nixnax 29:30de79d658f6 457 if (flags & (1<<1)) flagInfo[1]='S';
nixnax 29:30de79d658f6 458 if (flags & (1<<2)) flagInfo[2]='R';
nixnax 29:30de79d658f6 459 if (flags & (1<<3)) flagInfo[3]='P';
nixnax 29:30de79d658f6 460 if (flags & (1<<4)) flagInfo[4]='A';
nixnax 29:30de79d658f6 461 if (flags & (1<<5)) flagInfo[5]='U';
nixnax 29:30de79d658f6 462 if (flags & (1<<6)) flagInfo[6]='E';
nixnax 29:30de79d658f6 463 if (flags & (1<<7)) flagInfo[7]='C';
nixnax 29:30de79d658f6 464 if (flags & (1<<8)) flagInfo[8]='N';
nixnax 29:30de79d658f6 465 flagInfo[9]=0; // null terminate string
nixnax 29:30de79d658f6 466 if (v0) {
nixnax 29:30de79d658f6 467 debug(("Flags %s Seq %d Ack %d", flagInfo, seq, ack));
nixnax 29:30de79d658f6 468 }
nixnax 29:30de79d658f6 469 }
nixnax 29:30de79d658f6 470
nixnax 29:30de79d658f6 471 void tcpHandler()
nixnax 29:30de79d658f6 472 {
nixnax 26:11f4eb2663a7 473 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 29:30de79d658f6 474 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 475 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 476 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 477 char * pktLen = ipPkt+2; // 2 bytes
nixnax 28:1aa629be05e7 478 char * protocol = ipPkt+9; // 1 byte
nixnax 26:11f4eb2663a7 479 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 480 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 26:11f4eb2663a7 481 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 482 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 483
nixnax 29:30de79d658f6 484 ident[0] = ppp.ident>>8;
nixnax 29:30de79d658f6 485 ident[1] = ppp.ident>>0; // insert OUR ident
nixnax 29:30de79d658f6 486
nixnax 29:30de79d658f6 487 char * s = ppp.pkt.buf+4+headerSizeIP; // start of tcp packet
nixnax 26:11f4eb2663a7 488 char * srctcp = s + 0; // 2 bytes
nixnax 26:11f4eb2663a7 489 char * dsttcp = s + 2; // 2 bytes
nixnax 28:1aa629be05e7 490 char * seqtcp = s + 4; // 4 bytes
nixnax 28:1aa629be05e7 491 char * acktcp = s + 8; // 4 bytes
nixnax 28:1aa629be05e7 492 char * offset = s + 12; // 4 bits
nixnax 26:11f4eb2663a7 493 char * flagbitstcp = s + 12; // 9 bits
nixnax 26:11f4eb2663a7 494 char * checksumtcp = s + 16; // 2 bytes
nixnax 26:11f4eb2663a7 495
nixnax 26:11f4eb2663a7 496 int tcpSize = packetLength - headerSizeIP;
nixnax 28:1aa629be05e7 497 int tcpHeaderLen = ((offset[0]>>4)&0x0f)*4; // size of tcp header only
nixnax 28:1aa629be05e7 498 int dataLen = tcpSize - tcpHeaderLen; // data is what's left after the header
nixnax 29:30de79d658f6 499
nixnax 31:e000c1b9c565 500 unsigned int seq = (seqtcp[0]<<24)|(seqtcp[1]<<16)|(seqtcp[2]<<8)|(seqtcp[3]);
nixnax 31:e000c1b9c565 501 unsigned int ack = (acktcp[0]<<24)|(acktcp[1]<<16)|(acktcp[2]<<8)|(acktcp[3]);
nixnax 29:30de79d658f6 502
nixnax 28:1aa629be05e7 503 char * dataStart = s + tcpHeaderLen; // start of data
nixnax 29:30de79d658f6 504
nixnax 26:11f4eb2663a7 505 int flagsTCP = ((flagbitstcp[0]&1)<<8)|flagbitstcp[1];
nixnax 28:1aa629be05e7 506
nixnax 29:30de79d658f6 507 #define TCP_FLAG_ACK (1<<4)
nixnax 29:30de79d658f6 508 #define TCP_FLAG_SYN (1<<1)
nixnax 29:30de79d658f6 509 #define TCP_FLAG_PSH (1<<3)
nixnax 29:30de79d658f6 510 #define TCP_FLAG_RST (1<<2)
nixnax 29:30de79d658f6 511 #define TCP_FLAG_FIN (1<<0)
nixnax 28:1aa629be05e7 512
nixnax 29:30de79d658f6 513 // A sparse TCP flag interpreter that implements basic TCP connections from a single source
nixnax 29:30de79d658f6 514
nixnax 29:30de79d658f6 515 int incomingLen = dataLen; // remember length of incoming packet
nixnax 29:30de79d658f6 516 dataLen = 0; // most of our responses will have zero TCP data, only a header
nixnax 28:1aa629be05e7 517
nixnax 28:1aa629be05e7 518 if ( ((flagsTCP & ~TCP_FLAG_ACK) == 0) && ((flagsTCP & TCP_FLAG_ACK) != 0) ) {
nixnax 29:30de79d658f6 519 if (incomingLen > 0) { // they sent data in the ack
nixnax 29:30de79d658f6 520 ack = seq + incomingLen; // acknowledge the number of bytes they sent
nixnax 29:30de79d658f6 521 seq = ppp.seq; // confirm our current sequence position
nixnax 29:30de79d658f6 522 } else {
nixnax 29:30de79d658f6 523 if (ack <= ppp.seq) return; // their idea of our sequence is larger
nixnax 29:30de79d658f6 524 int temp = ack; // remember what they thought
nixnax 29:30de79d658f6 525 ack = seq; // ack their sequence
nixnax 29:30de79d658f6 526 ppp.seq = temp; // adopt their calculation of our sequence
nixnax 29:30de79d658f6 527 seq = ppp.seq;
nixnax 29:30de79d658f6 528 }
nixnax 29:30de79d658f6 529 } else if ( (flagsTCP & TCP_FLAG_FIN) != 0 ) { // got FIN
nixnax 29:30de79d658f6 530 flagbitstcp[1] |= TCP_FLAG_ACK; // do a fin-ack
nixnax 28:1aa629be05e7 531 ack = seq;
nixnax 28:1aa629be05e7 532 seq = ppp.seq;
nixnax 29:30de79d658f6 533 } else if ( (flagsTCP & TCP_FLAG_SYN) != 0 ) { // got SYN
nixnax 28:1aa629be05e7 534 flagbitstcp[1] |= TCP_FLAG_ACK; // do a syn-ack
nixnax 29:30de79d658f6 535 ack = seq + 1; // when you see SYN you increment their sequence
nixnax 29:30de79d658f6 536 seq = ppp.seq-1; // we cheat - our sequence will be one higher hereafter
nixnax 29:30de79d658f6 537 } else if ( (flagsTCP & TCP_FLAG_PSH) != 0 ) { // they are pushing data
nixnax 31:e000c1b9c565 538
nixnax 31:e000c1b9c565 539 // Ok, we are done with figuring out the flags. Now we start preparing to respond
nixnax 31:e000c1b9c565 540
nixnax 31:e000c1b9c565 541 int temp = ack;
nixnax 31:e000c1b9c565 542 ack = seq + incomingLen; // acknowledge the number of bytes they sent by adding it to seq
nixnax 31:e000c1b9c565 543 ppp.seq = temp; // adopt their calculation of our sequence number
nixnax 31:e000c1b9c565 544 seq = ppp.seq;
nixnax 31:e000c1b9c565 545
nixnax 31:e000c1b9c565 546 // let's check incoming text for an HTTP home page GET request
nixnax 31:e000c1b9c565 547 if ( strncmp(dataStart, "GET / HTTP/1.1", 14) == 0) {
nixnax 31:e000c1b9c565 548 flagbitstcp[1] = TCP_FLAG_FIN; // close connection after delivering page
nixnax 31:e000c1b9c565 549 dataLen = 15*32; // this block has to hold the web page below, but keep it under 1k
nixnax 31:e000c1b9c565 550 memset(dataStart,'x', dataLen ); // initialize the block
nixnax 31:e000c1b9c565 551 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 552 n=n+sprintf(n+dataStart,"HTTP/1.1 200 OK\r\nServer: PPP-Blinky\r\n"); // http header
nixnax 31:e000c1b9c565 553 n=n+sprintf(n+dataStart,"Content-Length: 378\r\n"); // http header
nixnax 31:e000c1b9c565 554 n=n+sprintf(n+dataStart,"Content-Type: text/html;charset=us-ascii\r\n\r\n"); // http header
nixnax 31:e000c1b9c565 555 int nHeader=n; // byte total of all headers
nixnax 31:e000c1b9c565 556 n=n+sprintf(n+dataStart,"<html><head><title>mbed-PPP-Blinky</title><script>window.onload=function()"); // html
nixnax 31:e000c1b9c565 557 n=n+sprintf(n+dataStart,"{setInterval(function(){function x(){return document.getElementById('w');};"); // html
nixnax 31:e000c1b9c565 558 n=n+sprintf(n+dataStart,"x().innerText = parseInt(x().innerText)+1;},100);};</script></head><body>"); // html
nixnax 31:e000c1b9c565 559 n=n+sprintf(n+dataStart,"<h1>mbed-PPP-Blinky Up and Running</h1><h1 id=\"w\" style=\"text-align:"); // html
nixnax 31:e000c1b9c565 560 n=n+sprintf(n+dataStart," center\";>0</h1><h1><a href=\"http://bit.ly/pppBlinky\">Source on mbed</h1></body></html>"); // html
nixnax 31:e000c1b9c565 561 int contentLength = dataLen-nHeader; // this is how to calculate Content-Length, but using curl -v is easier
nixnax 31:e000c1b9c565 562 contentLength = contentLength+0; // get around unreferenced variable warning
nixnax 31:e000c1b9c565 563 if (v0) {
nixnax 31:e000c1b9c565 564 debug(("HTTP GET dataLen %d*32=%d Header %d Content-Length %d Total %d Margin %d\n",dataLen/32,dataLen,nHeader,contentLength,n,dataLen-n-1));
nixnax 31:e000c1b9c565 565 }
nixnax 31:e000c1b9c565 566 } else if ( strncmp(dataStart, "GET /", 4) == 0) {
nixnax 31:e000c1b9c565 567 flagbitstcp[1] = TCP_FLAG_FIN; // close connection after delivering page
nixnax 31:e000c1b9c565 568 dataLen = 2*32; // this block has to hold the web page below, but keep it under 1k
nixnax 31:e000c1b9c565 569 memset(dataStart,'x', dataLen ); // initialize the block
nixnax 31:e000c1b9c565 570 int n=0; // number of bytes we have printed so far
nixnax 31:e000c1b9c565 571 n=n+sprintf(n+dataStart,"HTTP/1.1 404 Not Found\r\n\r\n\r\n\r\n"); // http header
nixnax 31:e000c1b9c565 572 if (v0) {
nixnax 31:e000c1b9c565 573 debug(("HTTP 404 Not Found\n"));
nixnax 31:e000c1b9c565 574 }
nixnax 29:30de79d658f6 575 }
nixnax 28:1aa629be05e7 576 }
nixnax 29:30de79d658f6 577
nixnax 29:30de79d658f6 578 // now we have to recalculate all the header sizes
nixnax 29:30de79d658f6 579
nixnax 28:1aa629be05e7 580 int newPacketSize = headerSizeIP + tcpHeaderLen + dataLen;
nixnax 29:30de79d658f6 581 pktLen[0] = (newPacketSize>>8);
nixnax 29:30de79d658f6 582 pktLen[1]=newPacketSize; // ip total packet size
nixnax 28:1aa629be05e7 583 ppp.pkt.len = newPacketSize+6; // ppp packet length
nixnax 28:1aa629be05e7 584 tcpSize = tcpHeaderLen + dataLen; // tcp packet size
nixnax 29:30de79d658f6 585
nixnax 28:1aa629be05e7 586 // redo all the header stuff
nixnax 29:30de79d658f6 587
nixnax 29:30de79d658f6 588 acktcp[0]=ack>>24;
nixnax 29:30de79d658f6 589 acktcp[1]=ack>>16;
nixnax 29:30de79d658f6 590 acktcp[2]=ack>>8;
nixnax 29:30de79d658f6 591 acktcp[3]=ack>>0; // save ack
nixnax 29:30de79d658f6 592 seqtcp[0]=seq>>24;
nixnax 29:30de79d658f6 593 seqtcp[1]=seq>>16;
nixnax 29:30de79d658f6 594 seqtcp[2]=seq>>8;
nixnax 29:30de79d658f6 595 seqtcp[3]=seq>>0; // save seq
nixnax 26:11f4eb2663a7 596
nixnax 29:30de79d658f6 597 char src[4];
nixnax 29:30de79d658f6 598 char dst[4];
nixnax 29:30de79d658f6 599 memcpy(src, srcAdr,4);
nixnax 29:30de79d658f6 600 memcpy(dst, dstAdr,4);
nixnax 29:30de79d658f6 601 memcpy(srcAdr, dst,4);
nixnax 29:30de79d658f6 602 memcpy(dstAdr, src,4); // swap ip address source/dest
nixnax 29:30de79d658f6 603 char psrc[2];
nixnax 29:30de79d658f6 604 char pdst[2];
nixnax 29:30de79d658f6 605 memcpy(psrc, srctcp,2);
nixnax 29:30de79d658f6 606 memcpy(pdst, dsttcp,2);
nixnax 29:30de79d658f6 607 memcpy(srctcp, pdst,2);
nixnax 29:30de79d658f6 608 memcpy(dsttcp, psrc,2); // swap ip port source/dest
nixnax 29:30de79d658f6 609
nixnax 29:30de79d658f6 610 headercheck[0]=0;
nixnax 29:30de79d658f6 611 headercheck[1]=0;
nixnax 29:30de79d658f6 612 headerCheckSum(); // redo the ip header checksum
nixnax 29:30de79d658f6 613 char pseudoHeader[12];
nixnax 29:30de79d658f6 614 int sum;
nixnax 29:30de79d658f6 615 char temp[12]; // for the terrible pseudoheader checksum
nixnax 26:11f4eb2663a7 616 memcpy( pseudoHeader+0, srcAdr, 8); // source and destination addresses.
nixnax 29:30de79d658f6 617 pseudoHeader[8]=0;
nixnax 29:30de79d658f6 618 pseudoHeader[9]=protocol[0];
nixnax 29:30de79d658f6 619 pseudoHeader[10]=tcpSize>>8;
nixnax 29:30de79d658f6 620 pseudoHeader[11]=tcpSize;
nixnax 26:11f4eb2663a7 621 memcpy(temp, s-12, 12); // keep a copy
nixnax 26:11f4eb2663a7 622 memcpy( s-12, pseudoHeader, 12); // put the header on the tcp packet
nixnax 29:30de79d658f6 623 checksumtcp[0]=0;
nixnax 29:30de79d658f6 624 checksumtcp[1]=0;
nixnax 29:30de79d658f6 625 sum=dataCheckSum(s-12,tcpSize+12); // update TCP checksum
nixnax 29:30de79d658f6 626 checksumtcp[0]=sum>>8;
nixnax 29:30de79d658f6 627 checksumtcp[1]=sum;
nixnax 26:11f4eb2663a7 628 memcpy( s-12, temp, 12); // overwrite the pseudoheader
nixnax 26:11f4eb2663a7 629 sendFrame(); // return the TCP packet
nixnax 29:30de79d658f6 630 }
nixnax 26:11f4eb2663a7 631
nixnax 29:30de79d658f6 632 void dumpDataTCP()
nixnax 29:30de79d658f6 633 {
nixnax 26:11f4eb2663a7 634 int ipPktLen = (ppp.pkt.buf[6]<<8)|ppp.pkt.buf[7]; // overall length of ip packet
nixnax 26:11f4eb2663a7 635 int ipHeaderLen = (ppp.pkt.buf[4]&0xf)*4; // length of ip header
nixnax 26:11f4eb2663a7 636 int tcpHeaderLen = ((ppp.pkt.buf[4+ipHeaderLen+12]>>4)&0xf)*4;; // length of tcp header
nixnax 26:11f4eb2663a7 637 int dataLen = ipPktLen - ipHeaderLen - tcpHeaderLen; // data is what's left after the two headers
nixnax 29:30de79d658f6 638 if (v1) {
nixnax 29:30de79d658f6 639 debug(("TCP %d ipHeader %d tcpHeader %d Data %d\n", ipPktLen, ipHeaderLen, tcpHeaderLen, dataLen)); // 1 for more verbose
nixnax 29:30de79d658f6 640 }
nixnax 29:30de79d658f6 641 if (dataLen > 0) {
nixnax 29:30de79d658f6 642 debug(("%s\n",ppp.pkt.buf+4+ipHeaderLen+tcpHeaderLen)); // show the data
nixnax 29:30de79d658f6 643 }
nixnax 29:30de79d658f6 644 }
nixnax 26:11f4eb2663a7 645
nixnax 29:30de79d658f6 646 void TCPpacket()
nixnax 29:30de79d658f6 647 {
nixnax 26:11f4eb2663a7 648 char * ipPkt = ppp.pkt.buf+4; // ip packet start
nixnax 26:11f4eb2663a7 649 char * version = ipPkt; // top 4 bits
nixnax 26:11f4eb2663a7 650 char * ihl = ipPkt; // bottom 4 bits
nixnax 26:11f4eb2663a7 651 char * dscp = ipPkt+1; // top 6 bits
nixnax 26:11f4eb2663a7 652 char * ecn = ipPkt+1; // lower 2 bits
nixnax 26:11f4eb2663a7 653 char * pktLen = ipPkt+2; // 2 bytes
nixnax 26:11f4eb2663a7 654 char * ident = ipPkt+4; // 2 bytes
nixnax 26:11f4eb2663a7 655 char * flags = ipPkt+6; // 2 bits
nixnax 26:11f4eb2663a7 656 char * ttl = ipPkt+8; // 1 byte
nixnax 26:11f4eb2663a7 657 char * protocol = ipPkt+9; // 1 byte
nixnax 29:30de79d658f6 658 char * headercheck= ipPkt+10; // 2 bytes
nixnax 26:11f4eb2663a7 659 char * srcAdr = ipPkt+12; // 4 bytes
nixnax 26:11f4eb2663a7 660 char * dstAdr = ipPkt+16; // 4 bytes = total of 20 bytes
nixnax 29:30de79d658f6 661
nixnax 29:30de79d658f6 662 int versionIP = (version[0]>>4)&0xf;
nixnax 26:11f4eb2663a7 663 int headerSizeIP = (ihl[0]&0xf)*4;
nixnax 26:11f4eb2663a7 664 int dscpIP = (dscp[0]>>2)&0x3f;
nixnax 26:11f4eb2663a7 665 int ecnIP = ecn[0]&3;
nixnax 26:11f4eb2663a7 666 int packetLength = (pktLen[0]<<8)|pktLen[1]; // ip total packet length
nixnax 26:11f4eb2663a7 667 int identIP = (ident[0]<<8)|ident[1];
nixnax 26:11f4eb2663a7 668 int flagsIP = flags[0]>>14&3;
nixnax 26:11f4eb2663a7 669 int ttlIP = ttl[0];
nixnax 26:11f4eb2663a7 670 int protocolIP = protocol[0];
nixnax 26:11f4eb2663a7 671 int checksumIP = (headercheck[0]<<8)|headercheck[1];
nixnax 29:30de79d658f6 672 char srcIP [16];
nixnax 29:30de79d658f6 673 snprintf(srcIP,16, "%d.%d.%d.%d", srcAdr[0],srcAdr[1],srcAdr[2],srcAdr[3]);
nixnax 29:30de79d658f6 674 char dstIP [16];
nixnax 29:30de79d658f6 675 snprintf(dstIP,16, "%d.%d.%d.%d", dstAdr[0],dstAdr[1],dstAdr[2],dstAdr[3]);
nixnax 29:30de79d658f6 676 if (v0) {
nixnax 29:30de79d658f6 677 debug(("IP %s %s v%d h%d d%d e%d L%d ",srcIP,dstIP,versionIP,headerSizeIP,dscpIP,ecnIP,packetLength));
nixnax 29:30de79d658f6 678 }
nixnax 29:30de79d658f6 679 if (v0) {
nixnax 29:30de79d658f6 680 debug(("i%04x f%d t%d p%d C%04x\n",identIP,flagsIP,ttlIP,protocolIP,checksumIP));
nixnax 29:30de79d658f6 681 }
nixnax 28:1aa629be05e7 682 dumpHeaderTCP();
nixnax 26:11f4eb2663a7 683 dumpDataTCP();
nixnax 26:11f4eb2663a7 684 tcpHandler();
nixnax 11:f58998c24f0b 685 }
nixnax 11:f58998c24f0b 686
nixnax 29:30de79d658f6 687 void otherProtocol()
nixnax 29:30de79d658f6 688 {
nixnax 29:30de79d658f6 689 debug(("Other IP protocol"));
nixnax 29:30de79d658f6 690 }
nixnax 26:11f4eb2663a7 691
nixnax 29:30de79d658f6 692 void IPframe()
nixnax 29:30de79d658f6 693 {
nixnax 10:74f8233f72c0 694 int protocol = ppp.pkt.buf[13];
nixnax 10:74f8233f72c0 695 switch (protocol) {
nixnax 29:30de79d658f6 696 case 1:
nixnax 29:30de79d658f6 697 ICMPpacket();
nixnax 29:30de79d658f6 698 break;
nixnax 29:30de79d658f6 699 case 2:
nixnax 29:30de79d658f6 700 IGMPpacket();
nixnax 29:30de79d658f6 701 break;
nixnax 29:30de79d658f6 702 case 17:
nixnax 29:30de79d658f6 703 UDPpacket();
nixnax 29:30de79d658f6 704 break;
nixnax 29:30de79d658f6 705 case 6:
nixnax 29:30de79d658f6 706 TCPpacket();
nixnax 29:30de79d658f6 707 break;
nixnax 29:30de79d658f6 708 default:
nixnax 29:30de79d658f6 709 otherProtocol();
nixnax 29:30de79d658f6 710 }
nixnax 29:30de79d658f6 711 }
nixnax 9:0992486d4a30 712
nixnax 29:30de79d658f6 713 void LCPconfReq()
nixnax 29:30de79d658f6 714 {
nixnax 15:b0154c910143 715 debug(("LCP Config "));
nixnax 9:0992486d4a30 716 if (ppp.pkt.buf[7] != 4) {
nixnax 11:f58998c24f0b 717 ppp.pkt.buf[4]=4; // allow only no options
nixnax 15:b0154c910143 718 debug(("Reject\n"));
nixnax 29:30de79d658f6 719 sendFrame();
nixnax 9:0992486d4a30 720 } else {
nixnax 9:0992486d4a30 721 ppp.pkt.buf[4]=2; // ack zero conf
nixnax 15:b0154c910143 722 debug(("Ack\n"));
nixnax 9:0992486d4a30 723 sendFrame();
nixnax 15:b0154c910143 724 debug(("LCP Ask\n"));
nixnax 11:f58998c24f0b 725 ppp.pkt.buf[4]=1; // request no options
nixnax 9:0992486d4a30 726 sendFrame();
nixnax 9:0992486d4a30 727 }
nixnax 9:0992486d4a30 728 }
nixnax 9:0992486d4a30 729
nixnax 29:30de79d658f6 730 void LCPconfAck()
nixnax 29:30de79d658f6 731 {
nixnax 15:b0154c910143 732 debug(("LCP Ack\n"));
nixnax 29:30de79d658f6 733 }
nixnax 9:0992486d4a30 734
nixnax 29:30de79d658f6 735 void LCPend()
nixnax 29:30de79d658f6 736 {
nixnax 29:30de79d658f6 737 debug(("LCP End\n"));
nixnax 29:30de79d658f6 738 ppp.online=0; // start hunting for connect string again
nixnax 29:30de79d658f6 739 ppp.pkt.buf[4]=6;
nixnax 29:30de79d658f6 740 sendFrame(); // acknowledge
nixnax 9:0992486d4a30 741 }
nixnax 9:0992486d4a30 742
nixnax 29:30de79d658f6 743 void LCPother()
nixnax 29:30de79d658f6 744 {
nixnax 29:30de79d658f6 745 debug(("LCP Other\n"));
nixnax 29:30de79d658f6 746 dumpFrame();
nixnax 29:30de79d658f6 747 }
nixnax 29:30de79d658f6 748
nixnax 29:30de79d658f6 749 void LCPframe()
nixnax 29:30de79d658f6 750 {
nixnax 29:30de79d658f6 751 int code = ppp.pkt.buf[4];
nixnax 29:30de79d658f6 752 switch (code) {
nixnax 29:30de79d658f6 753 case 1:
nixnax 29:30de79d658f6 754 LCPconfReq();
nixnax 29:30de79d658f6 755 break; // config request
nixnax 29:30de79d658f6 756 case 2:
nixnax 29:30de79d658f6 757 LCPconfAck();
nixnax 29:30de79d658f6 758 break; // config ack
nixnax 29:30de79d658f6 759 case 5:
nixnax 29:30de79d658f6 760 LCPend();
nixnax 29:30de79d658f6 761 break; // end connection
nixnax 29:30de79d658f6 762 default:
nixnax 29:30de79d658f6 763 LCPother();
nixnax 29:30de79d658f6 764 }
nixnax 9:0992486d4a30 765 }
nixnax 9:0992486d4a30 766
nixnax 29:30de79d658f6 767 void discardedFrame()
nixnax 29:30de79d658f6 768 {
nixnax 29:30de79d658f6 769 if (v0) {
nixnax 29:30de79d658f6 770 debug(("Dropping frame %02x %02x %02x %02x\n", ppp.pkt.buf[0],ppp.pkt.buf[1],ppp.pkt.buf[2],ppp.pkt.buf[3]));
nixnax 29:30de79d658f6 771 }
nixnax 9:0992486d4a30 772 }
nixnax 9:0992486d4a30 773
nixnax 29:30de79d658f6 774 void determinePacketType()
nixnax 29:30de79d658f6 775 {
nixnax 29:30de79d658f6 776 if ( ppp.pkt.buf[0] != 0xff ) {
nixnax 29:30de79d658f6 777 debug(("byte0 != ff\n"));
nixnax 29:30de79d658f6 778 return;
nixnax 29:30de79d658f6 779 }
nixnax 29:30de79d658f6 780 if ( ppp.pkt.buf[1] != 3 ) {
nixnax 29:30de79d658f6 781 debug(("byte1 != 3\n"));
nixnax 29:30de79d658f6 782 return;
nixnax 29:30de79d658f6 783 }
nixnax 29:30de79d658f6 784 if ( ppp.pkt.buf[3] != 0x21 ) {
nixnax 29:30de79d658f6 785 debug(("byte2 != 21\n"));
nixnax 29:30de79d658f6 786 return;
nixnax 29:30de79d658f6 787 }
nixnax 9:0992486d4a30 788 int packetType = ppp.pkt.buf[2];
nixnax 9:0992486d4a30 789 switch (packetType) {
nixnax 29:30de79d658f6 790 case 0xc0:
nixnax 29:30de79d658f6 791 LCPframe();
nixnax 29:30de79d658f6 792 break; // link control
nixnax 29:30de79d658f6 793 case 0x80:
nixnax 29:30de79d658f6 794 IPCPframe();
nixnax 29:30de79d658f6 795 break; // IP control
nixnax 29:30de79d658f6 796 case 0x00:
nixnax 29:30de79d658f6 797 IPframe();
nixnax 29:30de79d658f6 798 break; // IP itself
nixnax 29:30de79d658f6 799 default:
nixnax 29:30de79d658f6 800 discardedFrame();
nixnax 9:0992486d4a30 801 }
nixnax 29:30de79d658f6 802 }
nixnax 9:0992486d4a30 803
nixnax 29:30de79d658f6 804 void scanForConnectString()
nixnax 29:30de79d658f6 805 {
nixnax 9:0992486d4a30 806 if ( ppp.online==0 ) {
nixnax 15:b0154c910143 807 char * clientFound = strstr( (char *)rxbuf, "CLIENTCLIENT" ); // look for PC string
nixnax 29:30de79d658f6 808 if( clientFound ) {
nixnax 9:0992486d4a30 809 strcpy( clientFound, "FOUND!FOUND!" ); // overwrite so we don't get fixated
nixnax 9:0992486d4a30 810 pc.printf("CLIENTSERVER"); // respond to PC
nixnax 9:0992486d4a30 811 ppp.online=1; // we can stop looking for the string
nixnax 15:b0154c910143 812 debug(("Connect string found\n"));
nixnax 9:0992486d4a30 813 }
nixnax 9:0992486d4a30 814 }
nixnax 9:0992486d4a30 815 }
nixnax 9:0992486d4a30 816
nixnax 0:2cf4880c312a 817 int main()
nixnax 0:2cf4880c312a 818 {
nixnax 14:c65831c25aaa 819 pc.baud(115200); // USB virtual serial port
nixnax 15:b0154c910143 820 xx.baud(115200); // second serial port for debug(((((((( messages
nixnax 9:0992486d4a30 821 xx.puts("\x1b[2J\x1b[HReady\n"); // VT100 code for clear screen & home
nixnax 29:30de79d658f6 822
nixnax 9:0992486d4a30 823 pppInitStruct(); // initialize all the PPP properties
nixnax 4:a469050d5b80 824
nixnax 9:0992486d4a30 825 pc.attach(&rxHandler,Serial::RxIrq); // start the receive handler
nixnax 4:a469050d5b80 826
nixnax 29:30de79d658f6 827 int frameStartIndex, frameEndIndex;
nixnax 29:30de79d658f6 828 int frameBusy=0;
nixnax 4:a469050d5b80 829
nixnax 0:2cf4880c312a 830 while(1) {
nixnax 9:0992486d4a30 831 if ( ppp.online==0 ) scanForConnectString(); // try to connect
nixnax 22:00df34cd4d7e 832 while ( rxbufNotEmpty() ) {
nixnax 1:9e03798d4367 833 int rx = pc_getBuf();
nixnax 29:30de79d658f6 834 if (frameBusy) {
nixnax 4:a469050d5b80 835 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 836 frameBusy=0; // done gathering frame
nixnax 4:a469050d5b80 837 frameEndIndex=ppp.rx.tail-1; // remember where frame ends
nixnax 4:a469050d5b80 838 processFrame(frameStartIndex, frameEndIndex);
nixnax 4:a469050d5b80 839 }
nixnax 29:30de79d658f6 840 } else {
nixnax 4:a469050d5b80 841 if (rx==FRAME_7E) {
nixnax 4:a469050d5b80 842 frameBusy=1; // start gathering frame
nixnax 9:0992486d4a30 843 frameStartIndex=ppp.rx.tail; // remember where frame started
nixnax 4:a469050d5b80 844 }
nixnax 0:2cf4880c312a 845 }
nixnax 4:a469050d5b80 846 }
nixnax 7:ab147f5e97ac 847 }
nixnax 7:ab147f5e97ac 848 }